Genetic variation in an endemic salamander, Salamandra atra, using amplified fragment length polymorphism.

The pattern of genetic differentiation of the endemic alpine salamander, Salamandra atra, has been studied using amplified fragment length polymorphism (AFLP) from 11 populations throughout the range of the two currently recognized subspecies, atra and aurorae. Five different primer combinations produced 706 bands and were analyzed by constructing a phylogenetic tree using NJ and principal component analysis. Significant genetic variation was revealed by AFLP between and within populations but, our results show a lack of genetic structure. AFLP markers seems to be unsuitable to investigate complex and recent diversification.

Structural analysis of oligosaccharide-alditols released by reductive beta-elimination from oviducal mucins of Rana dalmatina.

The O-linked oligosaccharides of the jelly coat surrounding the eggs of Rana dalmantina were released by alkaline borohydride treatment. Low-molecular-mass, monosialyl oligosaccharide-alditols were isolated by anion-exchange chromatography and fractionated by consecutive normal-phase high-performance liquid chromatography on a silica-based alkylamine column. The structures of the oligosaccharide-alditols were determined by 400-MHz 1H-NMR spectroscopy in combination with matrix assisted laser desorption ionization-time of flight analysis. The five structures were identified range in size from trisaccharides to hexasaccharides, possessing a core consisting of Gal(beta 1-3)GalNAc-ol (core type 1). Novel oligosaccharide-alditols are: [formula: see text] The carbohydrate chains isolated from Rana dalmatina are different from those found in other amphibian species, in which the presence of species-specific material has been characterized. Since the role of carbohydrates appears more and more apparent during the fertilization process, the biodiversity of the O-linked oligosaccharides could support such a biological role.

[Thermodynamic studies of ontogenic rhythms of energy exchange in the alyte (an anuran amphibian)]. / Etude thermodynamique de l'ontogenèse des rhythmes de dépense énergétique chez l'alyte (amphibien anoure).

The total energy flux in an Amphibian was measured using a microcalorimetric technique throughout different stages of development. Simultaneous records of the individual activity (actography) allowed us to study circadian rhythms and their variations during ontogenesis. Acrophase of the energy exchanges take place at the beginning of the night in adults, tadpoles and juveniles of more than 9 months. However, there was a shift in the acrophase of the circadian rhythm in juveniles aged between 7 and 9 months. This could be an adaptation process which regulate competition within populations of the same species.

Direct and indirect calorimetry measurements during the annual growth cycle of juvenile frogs Rana ridibunda P.

A thermodynamic study of the energetic metabolism in juvenile amphibians was conducted over an annual cycle of growth. The total energy flux (delta H = enthalpy variation) was measured with direct microcalorimetry and accounted for the sum of all metabolic pathways. Indirect calorimetry, oxygen consumption measurements (VO2), provides the values for the oxidative metabolism-dependent energy. A comparison between the results of both techniques simultaneously performed, provides for the calculation of the energetic efficiency, which indicates the respective importance of aerobic and anaerobic metabolisms during the annual biological cycle. It is clear that oxidative metabolism does not represent all, nor even a constant percentage of the total energy production of the frog, Rana ridibunda. The ration (Formula: see text) varied between 0.72 and 1.00, according to the season and the feeding or fasting periods. These results are discussed with special reference to the ecophysiology and behaviour of this species.

[Construction and use of a very sensitive calorimeter adapted for biological research]. / Réalisation et mise au point d'un calorimètre de grande sensibilité adapté aux recherches biologiques.

The present conduction calorimeter was assembled to study the thermogenesis of whole organs or little Vertebrates. It is constituted of three essential parts : one aluminium calorimetric block, two cylindrical cells in plexiglass of 60,80 or 100 ml volume, two flux plates : the sensitive elements which permit differential measurements on a chart recorder. The whole system is thermoregulated.

[Comparative immunocytological study of prolactin and somatotropin cells in Alytes obstetricans (Laur.) tadpoles raised in groups or isolated]. / Etude cyto-immunologique comparative des cellules à prolactine et des cellules à somatohormone chez des Tétards d'Alytes obstetricans (Laur.) élevés en groupe ou isolés.

In the anterior pituitary of Alytes obstetricans Tadpoles in premetamorphic stages, two cell types were localized by cytoimmunological techniques: orangeophilic cells secreting a prolactin-like hormone in the anterior and median region and erythrosinophilic cells secreting growth hormone in a more caudal situation. Both cells are more numerous and stimulated in grouped Tadpoles than in isolated ones.